View full sizeThe Associated PressWill Roger be ready to hit dozens of high backhands like this one?

Here we go.

Roger Federer and Rafael Nadal, together again. This could be the great rivalry’s last gasp at the Grand Slam level, though we’ve been saying that since the 2009 Australian Open final.

So who will have the upper hand in tonight's semifinal? Let’s consider...

Federer is looking very sharp. He dismantled the tricky teen Bernard Tomic, piece by piece, in the fourth round. He breezily swept aside the powerful Juan Martin del Potro in the quarters. He’s been on a roll since the indoor fall season, winning the last Masters tournament of 2011 and the World Tour Finals. In the WTF, he put a straight-set thwoking on Nadal, including a set at love.

Nadal, meanwhile, has been slightly off for months. He’s been a little disgruntled in general, complaining about the length of the ATP schedule and how the rankings are tabulated. He had a weird knee-popping scare right before the tourney started and a shoulder problem before that. And he just spent four hours on court subduing big Tomas Berdych, who was willing to shake his opponent’s hand this time out.

So advantage Federer.

Or not.

It never can be simple when you put these two players together. The fact is, facing Roger Federer at a Grand Slam tournament always lifts Rafael Nadal. Since 2005, when Marat Safin turned back a match point in the AO semifinals to beat the Swiss, no one but Rafa has beaten Federer at a major when the 16-time Slam champion was at his best. (No, Roger did not play his best tennis in last year’s losses at the Australian Open, Wimbledon and the U.S. Open; he was in a bit of a funk for almost the entire year.) Nadal simply has an edge no one else has: His warrior spirit and that snapping lefty cross-court forehand are a deadly combination against Rog -- and most everyone else, too. And, undeniably, Melbourne’s slow, bouncy hard court suits Rafa in the match-up almost as nicely as Roland Garros’ clay. Roger knows he can “feel tennis,” as he once put it, and still lose to Nadal.

Federer fans -- I count myself among the brethren -- settle in for a rivalry match with Pepto-Bismol close at hand. Roger is one of the all-time great frontrunners, but against Nadal, no lead is safe. In the French Open final last year, Federer was up 5-2 in the first set and flying like an eagle. Federiacs across the globe wept and high-fived until their hands burned and their shoes filled with tears. Finally -- finally! -- Our Rog was bringing his own whip to bear in that alien red torture chamber where he had been put on the rack so many times before.

Nadal won the next seven games in a row.

"It's always pretty straightforward when we play each other ... because we know what to expect," Federer said after losing that match. "I'm not in any way frustrated with his play."

He’s not frustrated by Nadal on clay? That’s not good. It’s called acceptance, and it’s the last of the Kubler-Ross stages of grief. He’s come to terms with the fact that his dream of beating Nadal at Roland Garros is dead.

Of course, Melbourne isn’t Paris. But its courts are slower than those at Wimbledon or Flushing Meadows, and the bounce is higher.

So advantage Rafa?

Mmm, no. A win against Federer is exactly what Nadal needs right now, recharging his confidence and sling-shotting him back onto the path toward the No. 1 ranking. Still, I’m going to call this one for Federer anyway. The Swiss great knows his timeline for major-title contention is short. He appears to have his game face on out on court, and he seems relaxed and content in his press conferences. And the match will be played at night, which means the court might be slightly quicker.

All of that analytical stuff aside, I just feel it in my gut. This is his time against Nadal, right now, at age 30, two years since winning his last major title.

And for those who say it doesn’t really matter, because high-flying World No. 1 Novak Djokovic surely will be the guy on the other side of the net in the final?

I respond: Federer is 14-1 in major finals against men not named Rafael Nadal. And he’s already dispatched the guy who took that one victory from him (del Potro). The final will be a big deal, but not as big as Federer vs. Nadal.